Some substituted acetylpyrazine derivatives were prepared as the starting materials for the subsequent synthesis of thiosemicarbazones. General synthetic approach of all newly synthesized compounds is presented. All the thiosemicarbazone derivatives of acetylpyrazines were analyzed using the reversed phase high performance liquid chromatography (RP-HPLC) method for the lipophilicity measurement. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using end-capped non-polar C18 stationary RP column. In the present study the correlation between RP-HPLC retention parameter Log K (the logarithm of capacity factor K) and various calculated Log P values is shown. The relationships between the lipophilicity and the chemical structure of the studied compounds are discussed as well.

This paper describes novel synthetic approaches to polynorbornane molecular scaffolds substituted with peptides at various, well-defined positions. A library of norbornene building blocks with attached peptides was prepared. Alkene cyclobutane epoxide (ACE) coupling method was used as a key step reaction for connecting of two norbornene building blocks into bis-peptide scaffolds. Photodimerization of cyclobutene diesters offers alternative route to polynorbornane bis-peptides. Pyrrolo-peptides were used for preparation of peptide substituted 7-aza norbornenes. Unsymmetrical bis-peptide scaffolds were prepared by ACE coupling of peptide-norbornane epoxide with another norbornene-peptide block. Chemical elaboration of bridgehead dimethyl esters of ACE products or epoxide ACE reagents was also used for peptide attachment.

Symmetrical and asymmetrical triphenylene-based discotic liquid crystals with mixed ether-ester peripheral chains, the ester ones with a chiral carbon [ abbreviated as sym-TP(OCnH2n+1)3(OOCC*HClCH2CHMe2)3 and asym-TP(OCnH2n+1)3(OOCC*HClCH2CHMe2)3, n = 4 ~ 8，11 ] were synthesized. The phase transition temperature and the liquid crystal states were determined with polarized optical microscopy (POM) and differential scanning calorimetry (DSC). It was found that the symmetrical isomers have lower clearing points. Some of the discogens show as many as three kinds of columnar mesophases.

Alkyaltion of 2-hydroxy-4H-pyrido[1,2-a]pyrimidin-4-one (1) was investigated under solid-liquid phase transfer catalysis conditions (PTC), using tetrabutylammonium bromide and potassium carbonate. The reaction with alkyl halides led to the formation of various 2-alkoxy products, in fair yields. Reaction of compound 1 with epichlorohydrin and chloroacetonitrile, under the same PTC conditions, afforded novel O1,O3-disubstituted glycerol and oxazolo-pyridopyrimidone betain derivatives, respectively. Some 3-halo-, 3,3-dihalo and/or 2,3-dihalopyrido[1,2-a]pyrimidines were also prepared using different halogenating agents at different reaction conditions.

A series of pyrazolo[3,4-b]pyridine derivatives was synthesized by knoevenagel condensation of 5-aminopyrazoles aroylacetonitriles and triethyl/methylorthoesters and also by Conrad-limpach reaction of 5-aminopyrazole and ß-keto esters.

Nowadays the chromogenic substrates are very used for the quality control of different products such as water and food among others. These type of compounds are present as a component of some diagnostic media and allow to carry out the identification of different harmful bacteria. The enzimes excreted by the bacteries produce the lisis of the glycosidic linkage of the substrate showing a blue or magenta coloration [1]. One of these bacteria is the E. Coli that is identified by the 6-chloro-3-indolyl-b-D-glucuronide cyclohexylamine salt (Fig.1), among others[2,3], which present an indolic moiety as the aglycon part.

High pressure cycloaddition synthesis of electron donor-acceptor dyads possessing rigid polynorbornene framework and 7-silanorbornadiene moiety is described.

A series of fourteen lipophilic 2-substituted 5,7-di-tert-butylbenzoxazoles was prepared by the reaction of 2-amino-4,6-di-tert-butylphenol with appropriated aldehydes. The general synthetic approach of all newly synthesized compounds is presented. All the substituted 5,7-di-tert-butylbenzoxazoles derivatives were analyzed using the reversed phase high performance liquid chromatography (RP-HPLC) method for the lipophilicity measurement. The procedure was performed under isocratic conditions with methanol as an organic modifier in the mobile phase using end-capped non-polar C18 stationary RP column. In the present study the correlation between RP-HPLC retention parameter Log K (the logarithm of capacity factor K) and various calculated Log P values is shown. The relationships between the lipophilicity and the chemical structure of the studied compounds are discussed as well.

The DTBB-catalysed lithiation of Boc-protected alcohols, amines and thiols in THF at 0ºC led, after quenching with methanol, to the recovery of the free alcohols, amines and thiols in short reaction times and with very good yields. The procedure has been applied to primary, secondary and tertiary alcohols, secondary amines and a primary thiol. This method represents a reasonable alternative to the previously reported deprotection procedures.